The present invention relates to a non-woven fibrous product and more specifically to a non-woven blanket of mineral, man-made and natural fibers to which thermosetting resin may be added. The blanket may be formed into sheets, panels and complexly curved and configured products.
Non-woven fibrous products such as sheets and panels as well as other thin-wall products such as insulation and complexly curved and shaped panels formed from such planar products are known in the art.
In U.S. Pat. No. 2,483,405, two distinct types of fibers therein designated non-adhesive and potentially adhesive fibers are utilized to form a non-woven product. The potentially adhesive fibers typically consist of a thermoplastic material which are mixed with non-adhesive fibers to form a blanket, cord or other product such as a hat. The final product is formed by activating the potentially adhesive fibers through the application of heat, pressure or chemical solvents. Such activation binds the fibers together and forms a final product having substantially increased strength over the unactivated product.
U.S. Pat. No. 2,689,199 relates to non-woven porous, flexible fabrics prepared from masses of curled, entangled filaments. The filaments may be various materials such as thermoplastic polymers a-nd refractory fibers of glass, asbestos or steel. A fabric blanket consisting of curly, relatively short filaments is compressed and heat is applied to at least one side to coalesce the fibers into an imperforate film. Thus, a final product having an imperforate film on one or both faces may be provided or this product may be utilized to form multiple laminates. For example, an adhesive may be applied to the film surface of two layers of the product and a third layer of refractory fibers disposed between the film surfaces to form a laminate.
In U.S. Pat. No. 2,695,855, a felted fibrous structure into which is incorporated a rubber-like elastic material and a thermoplastic or thermosetting resin material is disclosed. The mat or felt includes carrier fibers of long knit staple cotton, rayon, nylon or glass fibers, filler fibers of cotton linter or nappers, natural or synthetic rubber and an appropriate resin. The resulting mat or felted structure of fibers intimately combined with the elastic material and resinous binder is used as a thermal or acoustical insulating material and for similar purposes.
U.S. Pat. No. 4,474,846 teaches the manufacture of a molded fibrous mat comprising cellulosic fibers preferably of wood, such as aspen, or paper, cotton, sisal, etc., carrier fibers of a thermoplastic material such as vinyl, polyester, nylon, polyvinyl chloride, etc. and a thermosetting resin. A suitable mix is defined as 85% by weight wood fibers, 10% polypropylene carrier fibers and 5% phenolic resin. After forming these ingredients into a mat, the carrier fibers may first be softened to give sufficient strength to the mat for subsequent handling. A secondary forming step may then be accomplished in which the thermosetting resin is activated to form a finished product.
U.S. Pat. No. 4,612,238 discloses and claims a composite laminated sheet consisting of a first layer of blended and extruded thermoplastic polymers, a particulate filler and short glass fibers, a similar, second layer of a synthetic thermoplastic polymer, particulate filler and short glass fibers and a reinforcing layer of a synthetic thermoplastic polymer, a long glass fiber mat and particulate filler. The first and second layers include an embossed surface having a plurality of projections which grip and retain the reinforcing layer to form a laminate.
It is apparent from the foregoing review of non-woven mats, blankets and felted structures that variations and improvements in such prior art products are not only possible but desirable.